Brazed component and method of forming a brazed joint therein

ABSTRACT

A brazed part includes two or more components that are brazed together and has related method of making. Using a method of locating parts relative to one another, an inter-component gap between the components may be formed. Subsequently, during brazing, flow control features formed along the inter-component gap may then be used to assist in the retention of the braze material between the components during brazing.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. non-provisionalpatent application Ser. No. 12/918,118 filed Nov. 24, 2010 whichrepresents the national stage of PCT International Application No.PCT/US2009/034697 filed Feb. 20, 2009, which claims the benefit of U.S.Provisional Application No. 61/066,804 entitled “Locating Joint andMethod of Locating” filed on Feb. 22, 2008, and U.S. ProvisionalApplication No. 61/101,457 entitled “Braze Flow Control” filed on Sep.30, 2008, the contents of all of which are incorporated herein byreference in their entirety for all purposes.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

BACKGROUND OF THE INVENTION

This disclosure relates to the brazing of two or more components. Inparticular, this disclosure relates to component structures forcontrolling the flow of brazing material between the components andmethods related to forming and using said structures to provide strongerbrazements between the components.

Brazing is a process by which two or more metallic components may bejoined to one another. The brazing process often begins with a solidbrazing material being placed in a reservoir that is in fluidcommunication with a volume between the surfaces of the components to bejoined. The brazing material has a low melting temperature such that,when the brazing material is heated, the brazing material forms a liquidphase that fills the volume between the two components. Typically,gravity and capillary action are used to transport the liquid phase ofthe brazing material from the reservoir to the volume between the twocomponents.

The liquid phase of the brazing material contacts and wets the surfacesof each of the components. This contact between the liquid phase of thebrazing material and the metallic surfaces to be joined dissolves a thinlayer of each of the metallic surfaces. The liquid phase of the brazingmaterial and the dissolved component metals form a liquid alloy. Uponsolidification, the liquid alloy forms a bond between the components,thus joining them.

The strength of the brazed joint may be compromised if the brazingsurfaces are not properly wetted by the brazing material. Improperwetting may occur if the distance between the surfaces to be brazed isirregular or if there is not enough brazing material to fill the gapbetween the components. If the brazing material does not completely fillthe gap between the components, then this defect weakens the brazedjoint and makes it more susceptible to mechanical failure.

As the assembled, but not yet brazed, components are typically handledbefore brazing, some misalignment of the components is common. Suchmisalignment can alter the uniformity and the consistency of the spacingof the components, adversely affecting the wetting of the surfacesduring brazing and creating the potential for loss of some of thebrazing material via overflow.

Further, if mishandling has severely misaligned the components, then theoverall dimensional requirements for the final brazed part may not bemet, meaning that the part will need to be scrapped or subjected tocostly post-brazing secondary operations.

Hence, a need exists for improvements in the brazing process to providemechanically strong brazed joints. In particular, there is a need forbetter control over the brazing material during the formation of thebrazed joint.

SUMMARY OF THE INVENTION

A brazed part is disclosed including a first component and a secondcomponent. The components are brazed together along an inter-componentgap between their respective brazing surfaces by a brazing material. Thebrazed part includes a plurality of locating joints defining theinter-component gap between the brazing surfaces. Each of the locatingjoints includes a projection with an arcuate convex surface on one ofthe components and a corresponding recess with opposite-facing angledwalls on the other of the components. In each of the locating joints,the projection is located in the corresponding recess and is supportedby contact between the arcuate convex surface and at least one of theangled walls. During brazing, the brazing material is heated to form aliquid that flows through the inter-component gap to wet the brazingsurfaces and join them upon solidification.

In one form, the brazed part may further include a flow control featureformed on at least one of the first component and the second component.The flow control feature is formed proximate a periphery of theinter-component gap. The flow control feature may be a lip thatincreases a distance of the inter-component gap between the firstcomponent and the second component. The lip may inhibit a capillaryaction of the brazing material past the periphery of the inter-componentgap during the brazing process. The flow control feature may also be adam that is vertically raised from the brazing surface of at least oneof the first component and the second component. The dam inhibits theflow of the brazing material past the dam to substantially retain thebrazing material within the inter-component gap.

In another form, the brazed part may further include a flow controlfeature formed between a first section and second section of theinter-component gap, the first section and second section not being inthe same plane. The flow control feature may be a lip that reduces acapillary force of the brazing material proximate to the lip to inhibitthe flow of the brazing material from the first section to the secondsection of the inter-component gap during a brazing process. In thisway, when the brazed part is subjected to a rotational stress about anaxis resulting in an applied shear stress between the first and sectioncomponents, at least one the first section and second section extendalong an essentially axial direction to increase an area over which theshear stress is applied.

In yet another form, the brazed part may be a planetary gear carrier. Inthis form, the first component is a cage having at least three legs,each of the legs having one of a projection with an arcuate convexsurface and a recess with opposite-facing angled walls. The secondcomponent is a plate having three locating joint halves, each of thelocating joint halves being one of a projection with an arcuate convexsurface and a recess with opposite-facing angled walls and mating withthe locating joint half on one of the at least three legs to definethree locating joints and the inter-component gap between the cage andthe plate.

In still yet another form, the arcuate convex surface is semi-sphericaland each of the angled walls contacted by the arcuate convex surface areessentially planar.

A method of locating two or more components relative to one another isalso disclosed. The method includes providing a first component and asecond component. Each component has a plurality of locating jointportions, each of the locating joint portions being one of a projectionwith an arcuate convex surface and a recess with opposite-facing angledwalls. The method further includes locating the first component relativeto the second component by mating the plurality of locating jointportions of the first component with the plurality of locating jointportions of the second component to form a plurality of locating joints.Each of the plurality of locating joints includes a projection and arecess such that the arcuate convex surface of the projection contactsat least one of the opposite-facing angled walls of the recess.

In one form, the step of locating the first component relative to thesecond component may include forming at least three locating joints thatdefine an inter-component gap between the first component and the secondcomponent.

In this form, the method may further include the steps of applying abrazing material to at least one of the first component and the secondcomponent and brazing the first component and the second componenttogether along the inter-component gap using the brazing material.

The step of applying the brazing material may include placing thebrazing material in a blind hole. Alternatively or in combination, thestep of applying the brazing material may include placing the brazingmaterial in the recess of the locating joint. In either form, the stepof brazing the first component and the second component togetherincludes melting the brazing material such that the brazing materialmoves to and wets at least a portion of the inter-component gap betweenthe first component and the second component by capillary action.

The step of applying the brazing material to at least one of the firstcomponent and the second component may occur before locating the firstcomponent relative to the second component. In this form, during thebrazing step, as the brazing material melts, a distance between thefirst component and the second component decreases and locates the firstcomponent relative to the second component by self-seating the locatingjoint portions of the first component in the locating joint portions ofthe second component to form the locating joints.

A method of controlling a flow of a brazing material during a brazingprocess is also disclosed. The method includes providing a firstcomponent and a second component. The first component and the secondcomponent each have a brazing surface. At least one of the firstcomponent and the second component have a flow control feature formedthereon. The method further includes locating the first componentrelative to the second component such that the brazing surface of thefirst component and the brazing surface of the second component have aninter-component gap therebetween. The method further includes providinga brazing material and heating the brazing material to at least amelting point of the brazing material to form a liquid that flowsthrough the inter-component gap by wetting the brazing surfaces of thefirst component and the second component. The flow control featuresubstantially retains the brazing material within the inter-componentgap to form a brazed joint between the first component and the secondcomponent.

In one form of the method, the first component and the second componenteach may have at least three locating joint portions. Each of the atleast three locating joint portions are one of a projection with anarcuate convex surface and a recess with opposite-facing angled walls.In this form, the step of locating the first component relative to thesecond component includes mating at least three locating joint portionsof the first component and at least three locating joint portions of thesecond component to form at least three locating joints that define theinter-component gap. Each of the at least three locating joints includea projection and a recess, such that the arcuate convex surface of theprojection contacts at least one of the opposite-facing angled walls ofthe recess.

In another form of the method, the flow control feature may be a damformed proximate a periphery of the inter-component gap. The dam is aportion that is vertically raised such that, during the heating of thebrazing material, the flow of the brazing material past the dam isinhibited.

In yet another form of the invention, the flow control feature may be alip formed proximate a periphery of the inter-component gap. The lip isa portion that increases a distance of the inter-component gap proximatethe periphery of the inter-component gap to inhibit the capillary actionof the brazing material past the periphery of the inter-component gapduring brazing.

In still yet another form, the flow control feature may be formedbetween two sections of the inter-component gap that are not in the sameplane as one another and the flow control feature reduces a capillaryforce of the braze material proximate the flow control feature to reducethe flow of material from one of the two sections to the other. The twosections may include an essentially horizontal first section along aplane and a second section that is at an angle to the essentiallyhorizontal section. In that form, the flow control feature is a lip thatincreases the inter-component gap along an intersection between thefirst section and the second section.

Another brazed part is also disclosed having a first component and asecond component with a brazing material located in an inter-componentgap therebetween. The brazing material joins a brazing surface of thefirst component and a brazing surface of the second component togetherat a brazed joint. The brazed joint is formed during a brazing processin which the brazing material melts to flow across the inter-componentgap and then solidify to form the brazed joint. The brazed part includesa flow control feature formed on at least one of the first component andthe second component. The flow control feature substantially retains thebrazing material within the inter-component gap.

In one form of the brazed part, there may be at least three locatingjoint portions formed in each of the first component and the secondcomponent. Each of the locating joint portions are one of a projectionwith an arcuate convex surface and a recess with opposite-facing angledwalls. The locating joint portions of the first component and the atleast three locating joint portions of the second component mating toform at least three locating joints that define the inter-component gap.Each of the locating joints including a projection and a recess, suchthat the arcuate convex surface of the projection contacts at least oneof the opposite-facing angled walls of the recess.

In another form, the flow control feature may be a lip that locallyincreases the inter-component gap between the first component and secondcomponent. The lip may inhibit a capillary action of the brazingmaterial during the brazing process.

In yet another form, the flow control feature may be a dam that isvertically raised from the brazing surface of at least one of the firstcomponent and the second component. The dam inhibits the flow of thebrazing material from the inter-component gap past the dam.

In still another form, the inter-component gap may include an outerperiphery and an inner periphery each having a flow control featureformed thereon.

In still yet another form, the flow control feature may be a lip formedbetween two sections of the inter-component gap that are not in the sameplane as one another. The lip reduces a capillary force of the brazematerial proximate the flow control feature to reduce the flow ofmaterial from one of the two sections to the other.

In still yet another form, the flow control feature may be configured tostop the progression of a meniscus of the brazed material in liquid formpast the flow control feature during the brazing process by locallyincreasing the inter-component gap

Thus, a brazed part and methods related to forming a brazed part areprovided that solve many of the aforementioned problems associated withbrazing. Using the structures and methods described herein, it ispossible to locate two or more components relative to one another in amanner that provides a uniform and consistent gap between the surfaces.As the joints are self-locating, some mishandling of the parts will notupset the positioning of the parts relative to one another. Thisminimizes the likelihood of the gap increasing to the point at whichcapillary action of the brazing material is insufficient to entirelyfill the gap, potentially resulting in the localized overflow of thebrazing material while in liquid form. Further, the flow controlfeatures and method of controlling the flow of the brazing material helpto retain all of the brazing material in the gap and allow forbrazements having complex geometries that would be otherwise difficult,if not impossible, to achieve without such use of such flow controlfeatures.

These and still other advantages of the invention will be apparent fromthe detailed description and drawings. What follows is merely adescription of some preferred embodiments of the present invention. Toassess the full scope of the invention the claims should be looked to asthese preferred embodiments are not intended to be the only embodimentswithin the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional side view of a locating joint;

FIG. 2 is a perspective view of one half of the locating joint includinga projection;

FIG. 3 is a perspective view of the other half of the locating jointincluding a recess with oppositely-facing angled walls;

FIG. 4 is a side elevation view of a planetary gear carrier;

FIG. 5 is a cross-sectional view of the planetary gear carrier;

FIG. 6A is a cross-sectional side view of two components arranged nextto one another prior to brazing in which each of the components having aflow control feature;

FIG. 6B is a detailed cross-sectional side view of FIG. 6A;

FIG. 7A is a cross-sectional side view of two components having lipsformed about the peripheries of an inter-component gap and having a stepformed in the inter-component gap, the two components being positionednext to one another prior to brazing;

FIG. 7B is a detailed cross-sectional side view of FIG. 7A;

FIG. 7C is a detailed cross-sectional side view of FIG. 7A after thebrazing material has melted to braze the two components together;

FIG. 8 is a detailed cross-sectional side view of two components similarto FIGS. 7A-7C, but with one of the components having a dam instead of alip on the outer periphery of the inter-component gap;

FIG. 9 is a detailed cross-sectional side view of two components similarto FIG. 8, but with an angled step formed in the inter-component gap;

FIG. 10A is a cross-sectional side view of two components arranged nextto one another prior to brazing, the two components having a large stepformed in the inter-component gap with a lip formed thereabout; and

FIG. 10B is a detailed cross-sectional side view of FIG. 10A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to FIG. 1, a locating joint 110 is shown. The locatingjoint 110 includes a projection 112 having an arcuate convex surface 113on a first component 114 and a recess 116 on a second component 118.

Referring now to FIGS. 1 and 2, the projection 112 extends from asurface 120 of the first component 114 and may include a transitioningradius 122 between the surface 120 and the arcuate convex surface 113.It should be appreciated that the arcuate convex surface 113 may haveother surface geometries including, but not limited to, a semi-sphericalsurface having a constant radius. The projection 112 may be referred toas the male mating component or by other similar terms.

Referring now to FIGS. 1 and 3, the recess 116 extends into a surface124 of the second component 118 and includes opposite-facing angledwalls 126 extending down to a bottom 128 of the recess 116. Like theprojection 112, the recess 116 may have transitioning radii 130 and 132between the surface 124, the angled walls 126, and the bottom 128. Asshown, the opposite-facing angled walls 126 are flat, planar surfaces.The recess 116 extends further in a direction parallel to theopposite-facing angled walls 126 than in the direction perpendicular tothe opposite-facing angled walls 126. The recess 116 might be generallydescribed as a rounded rectangular-shaped recess that generally tapersinward as the recess 116 extends downward to the bottom 128. The recess116 may be referred to as the female mating component or by othersimilar terms. Generically, the projection 112 and the recess 116 mayeach be referred to as a locating joint half.

During the formation of the locating joint 110, the arcuate convexsurface 113 contacts the opposite-facing angled walls 126 of the recess116 at one or both of contact points 134 and 136. Given the geometry ofthe arcuate convex surface 113 and the opposite-facing angled walls 126,the projection 112 only tangentially touches the recess 116 at one orboth of the two contact points 134 and 136.

Although two contact points 134 and 136 are shown in FIG. 1, it ispossible that the arcuate convex surface 113 may only tangentiallycontact one of the opposite-facing angled walls 126. As will bedescribed in further detail below, there may only be a single point ofcontact if one of the first component 114 and second component 118 arerestricted at a location outside of the cross-section shown in FIG. 1.

Given the surface geometries of the projection 112 and the recess 116,an inter-component gap 138 is created between the surface 120 of thefirst component 114 and the surface 124 of the second component 118 whenthe projection 112 and recess 116 mate. By altering the geometry of thearcuate convex surface 113 of the projection 112, the width of therecess 116, or the pitch of the opposite-facing angled walls 126 of therecess 116, the contact points 134 and 136 can be modified such that thegap 138 can be controlled. It should be noted that while the gap 138 isconstant and uniform as shown, that the nature of this gap 138 is atleast in part due to features outside of the cross-sectional view ofFIG. 1 as will be described in further detail below.

FIGS. 1-3 have been used to show the structure of one form of a singlelocating joint. It is contemplated that multiple locating joints couldbe incorporated into a single assembly including two or more componentsto define points of contact between the components and, thus, theinter-component gap between the components.

For example, in FIGS. 2-5, a planetary gear carrier is shown thatincludes three locating joints between a plate and a cage having threelegs. Thus, the projection 112 shown on the surface 120 of the plate inFIG. 2 is a single representative of the three projections found on theplate. Likewise, the recess 116 shown on the surface 124 of the leg inFIG. 3 is representative of the recess found on each of the three legsof the cage.

For ease of reference, the numbers used in FIGS. 2 and 3 to describe thefeatures of one of the joints will be used generically to refer tosimilar features in the planetary gear carrier (e.g., the referencenumber 116 in FIG. 3 that refers to a single recess on the componentwill be used refer to the recesses found on each of the legs).

Referring now to FIGS. 4 and 5, the first component 114 is located withrespect to the second component 118 at three locating joints 144, 146,and 148, which are all similar to the locating joint 110, to form aplanetary gear carrier 150. As shown, the first component 114 is a plateand the second component 118 is a “cage” or “spider” having three legs152, 154, and 156 connected at a base 158. The first component 114 orplate has three projections 112, each similar to the projection 112shown in FIG. 2. Likewise, each of the three legs 152, 154, and 156 hasa recess 116 similar to the recess 116 shown in FIG. 3. The threeprojections 112 on the plate are placed into the three recesses 116 ofthe legs 152, 154, and 156 forming the three locating joints 144, 146,and 148.

Although an overhead view is not shown of the planetary gear carrier150, the planetary gear carrier 150 is roughly circular in a top planview, and the center of the legs 152, 154, and 156 (and the recessescontained thereon) are all spaced 120 degrees apart about an axis Awhich runs vertically through the center of the planetary gear carrier150. In this form, it is preferable if the opposite-facing angled walls126, for contacting the arcuate convex surfaces 113, generally extend ina direction towards the axis A. However, not all of the contacting wallsneed extend in a direction towards a central point or axis. Similarly,the centers of the projections 112 are also spaced 120 degrees apartabout the axis A on the plate.

Thus, when the projections 112 are received into the recesses 116, thelocating joints 144, 146, and 148 align the centers of the projections112 into centers of the recesses 116 and simultaneously radially alignthe first component 114 and the second component 118 about the axis A.Ideally, each of the arcuate convex surfaces 113 of the projections 112make a point of contact with the each of the opposite-facing angledwalls 126 (thus providing two points of contact per locating joint).However, it is contemplated that more than likely a “best fit” situationwill occur if any of the projections 112 or recesses 116 deviate too farfrom their target location on the components 114 and 118. Thus, in mostsituations, only one point of contact will exist in a given locatingjoint.

This alignment of the first component 114 relative to the secondcomponent 118 by the locating joints 144, 146, and 148 provides manybenefits.

The locating joints 144, 146, and 148 reduce the likelihood ofmisassembly during handling. In particular, the steep pilot angle of theangled walls 126 and the depth of engagement of the projection 112 intothe recess 116 prevent the unintended shifting of the first component114 relative to the second component 118.

Additionally, these three locating joints 144, 146, and 148 providepoints of contact that define the gap 138 between each of the surfaces124 of the legs 152, 154, and 156 of the cage and the surface 120 of theplate. Assuming that each of the locating joints 144, 146, and 148 havea projection 112 mating with the recess 116 in a relatively similar way,the gap 138 will be uniform and consistent between the surfaces 124 ofeach of the legs and surface 120 of the plate.

Although such a gap is not necessarily formed (depending on the geometryof the locating joint halves), the formation of the gap 138 isbeneficial if the two components are to be brazed together. According toone aspect of the invention, the first component 114 and the secondcomponent 118 may be brazed together after locating the first component114 and the second component 118 with respect to one another. The gap138 may provide a controlled “channel” having relatively uniform spacingbetween the surfaces 120 and 124 for promoting the capillary action of aliquid phase of a brazing material between the surfaces 120 and 124.

From FIGS. 2 and 3, it can be seen that the first component 114 has anetwork of channels 140 that run along the surface 120 of the firstcomponent 114. The outer edge of the network of channels 140 roughlymatches the outer profile of the legs of the second component 118. Thesecond component 118 also has blind holes 142 for capturing pellets ofbrazing material (not shown).

When the first and second components 114 and 118 are located using thelocating joints 144, 146 and 148, and heated to a temperature above themelting temperature of the brazing material, the brazing material meltsout of the blind holes 142. Preferably, during brazing, the orientationof the blind holes 142 face downward such that the brazing material mayrun out of the blind holes 142. By gravity and capillary action, thebrazing material fills the gap 138 between the first component 114 andthe second component 118. The network of channels 140 captures andprevents the brazing material from flowing past the outer edge of thenetwork of channels 140 and onto other surfaces of the components. Inthis way, the brazing material can flow into the controlled gap betweenthe surfaces 120 and 124 of each of the legs and the plate. As will bedescribed in more detail below, there may be additional flow controlfeatures that restrict the flow patterns of the brazing material.

The brazing material is selected such that when it contacts the surfaces120 and 124, the chemistry at the surface permits the formation of aliquid alloy between the brazing material and each of the components.Upon cooling, this liquid alloy containing both the brazing material andthe component material forms a solid layer 160 that bonds the twocomponents together.

The planetary gear carrier 150 shown in FIGS. 2-5 would typically bebrazed using a sinter brazing process as one or both of the cage andplate may be a powder metal part. However, there is nothing requiringthat one of the components be made of powder metal. Thus, it is alsocontemplated that both of the components could be fully dense materials.

Although a method of brazing has been shown in which the brazingmaterial flows out of blind holes 142, other brazing techniques may beused. For example, the brazing compound may be a flat, stamped sheetplaced over the surface of one of the components. Likewise, pastesincluding brazing compounds could be applied to one or more of thecomponents before the brazing process occurs.

Although FIGS. 1-5 show locating joints in which the projections 112contact the recesses 116 prior to the brazing process, it iscontemplated that a brazing compound might be added between the surfaces120 and 124 such that the projections 112 do not initially contact therecesses 116. In this case, upon melting, at least a portion of thebrazing material would be sandwiched out of the gap between thecomponents or absorbed by the components (as may be the case in a porouspowder metal component), moving the components together as the locatingjoints self-seat. Thus, the locating joints may perform the locatingfunction as the brazing process occurs.

Likewise, brazing material may be added to the bottom 128 of therecesses 116 such that the projections 112 and the recesses 116 do notinitially contact one another. However, during the brazing process, theprojections 112 and the recesses 116 may self-seat as the brazingmaterial flows from the recesses 116. If the brazing material is placedin the recesses 116, then it may be preferable to have the recesses 116located above the projections 112, such that gravity aids the flow ofthe brazing material out of the locating joint and into the gaps 138.

Further, the recesses 116 and the blind holes 142 may be through-holessuch that brazing material may be introduced after the projections 112and recesses 116 have already formed points of contact.

Additionally, although the embodiment shown in FIGS. 2-5 employs amethod including brazing two components together, the locating joint 110could be used in any one of a number of other joining methods. Forexample, the locating feature may be applied to other joining methodssuch as, for example, riveting, welding, staking, providing central andradial locating for fasteners such as bolts and the like. Moreover, thelocating joint 110 may be of use in applications requiring the locating,but not necessarily the joining, of two or more components.

It should be further appreciated that although only two components havebeen shown to be located using the locating method and locating joints110, that more than two components may be joined using the method andlocating joints described herein. For example, more than two componentsmay be stacked into a multi-component assembly.

Further, although three locating joints have been shown in theembodiment shown in FIGS. 2-5, less or more than three locating jointsmay be suitable for locating components relative to one another. Forexample, two locating joints 110 may be used to locate two items about aline. In this case, the angled walls of the recess in one of thelocating joints would not be parallel with the angled walls of therecess in the other locating joint. In yet another example, more thanthree locating joints may be made available. In this case, only three ofthe more than three locating joints form points of contact and other,out-of-plane locator and redundant joint halves, would not contact oneanother.

Moreover, when multiple locating joints are used, it is contemplated asingle component may have more than one type of locating joint half(i.e., projection or recess). For example, a first component may havetwo projections and a single recess. In this case, by necessity thesecond component would need to have two recesses and a singleprojection, properly positioned, to mate with the first component.

The above-disclosed locating joints help to provide a consistent anduniform gap between multiple components that facilitates improvedcapillary action of a braze material between the components to provide amechanically strong brazed joint. Disclosed below are further structuresand methods for retaining the braze material within the gap between thecomponents such that, during brazing, little or no braze materialescapes the inter-component gap. These embodiments may be used with orwithout the locating joints, but for the above-mentioned reasons, thecombination of the above-described locating joints with thebelow-described flow control features will typically provide the mostadvantageous results.

Referring now to FIGS. 6A and 6B, a first component 210 is shown placedon top of a second component 212 prior to a brazing operation. In oneform, and as shown, the first component 210 may be a cylindrical hub andthe second component 212 may be a scroll flange. The first component 210and the second component 212 share a central axis B-B. These componentsmay be powder metal components or formed using other common metalforming techniques.

The first component 210 has a brazing surface 214 and the secondcomponent 212 has a brazing surface 216. The first component 210 and thesecond component 212 are located relative to one another such that aninter-component gap 218 is formed between the brazing surface 214 of thefirst component 210 and the brazing surface 216 of the second component212. As shown, the inter-component gap 218 is slanted slightly upward asit extends away from the central axis B-B, giving the inter-componentgap 218 a frusto-conical shape.

Although not shown, the inter-component gap 218 may be formed by placingspacers between the first component 210 and the second component 212 toseparate the two components or by using the locating joints describedabove. The use of locating joints have advantages over using standardspacers. The locating joint halves allow the first component 210 and thesecond component 212 to self-locate relative to one another.Additionally, the use of locating joints reduces the likelihood ofdisturbing the positioning of the components by mishandling.

Regardless of the spacing used, the distance between the brazingsurfaces 214 and 216 is preferably relatively consistent across theportions of the inter-component gap 218 that will be brazed together. Aswill be described in further detail later, the distance between thebrazing surfaces 214 and 216 should be appropriately chosen for thebrazing material to ensure that both surfaces are wetted by the brazingmaterial and that capillary action of the liquid braze material canoccur between the brazing surfaces of 214 and 216.

About the periphery of the brazing surfaces 214 and 216, flow controlfeatures are formed. For example, on the first component 210, a lip 220is formed near the outer periphery of the inter-component gap 218, wherethe inter-component gap widens. On the second component 212, a moat 222is formed proximate the inner periphery of the inter-component gap 218.During the brazing process, these flow control features will direct andrestrict the flow of the braze material across the inter-component gap218.

Although in the form shown in FIGS. 6A and 6B, the flow control featuresinclude a lip on one component and a moat on the other, each brazingsurface may have more than one flow control feature and each peripheryof the inter component gap could have more than one flow controlfeature. The flow control features can include, but are not limited to,lips, dams, fillets, chamfers, moats, and the like.

During the brazing operation, the brazing surfaces 214 and 216 will bebrazed together to form a brazed joint between the first component 210and the second component 212. A charge of a brazing material 224 ispositioned proximate the inter-component gap 218. The brazing material224 is heated to at least a melting point of the brazing material 224,but a temperature below the melting point of the first and secondcomponents 210 and 212. The melted brazing material 224 will flow intothe inter-component gap 218 between the brazing surface 214 of the firstcomponent 210 and the brazing surface 216 of the second component 212.The brazing material 224 will wet the brazing surfaces 214, 216 and fillthe inter-component gap 218 via capillary action.

The flow control features shown in FIGS. 6A and 6B assist in directingand restricting the flow of the brazing material 224 in liquid form. Inthe configuration shown in FIGS. 6A and 6B, the charge of the brazingmaterial 224 melts and flows into the moat 222 around the innerperiphery of the inter-component gap 218. The moat 222 directs thebrazing material 224 around the circumference of the inner periphery.When the moat 222 is filled with brazing material 224, the brazingmaterial 224 begins to flow into the inter-component gap 218 wettingboth of the surfaces and moving upward and away from the central axisB-B via capillary action. Once the brazing material 224 reaches theouter periphery of the inter-component gap 218, the lip 220 locallyincreases the spacing between the first component 210 and the secondcomponent 212.

Because the capillary action is at least partially dependent on thespacing between the brazing surfaces 214 and 216 and the contact anglebetween the liquid phase and the solid walls, when the spacing betweenthe brazing surfaces 214 and 216 is increased, the brazing material 224is not wicked past the lip 220. Specifically, the surface tension of themeniscus of the brazing material 224 is sufficiently great to preventthe brazing material 224 from flowing past the lip 220 (given theinter-component gap and the change in the contact angle at the flowcontrol feature). This prevents the loss of brazing material 224 as theresult of spilling over the side of the second component 212 and helpsto ensure that none of the brazing material 224 is lost. If brazingmaterial 224 is lost over the edge, then there may be insufficientbrazing material 224 available to fill the inter-component gap 218 andform the brazing joint over the desired area of the inter-component gap218.

As described above, in its liquid phase, the brazing material 224 willdissolve a thin layer of each of the brazing surfaces 214, 216. Uponcooling, the brazing material 224 will solidify, joining the firstcomponent 210 and the second component 212 at a brazed joint.

FIGS. 6A and 6B show one embodiment of the present invention. Insubsequently described embodiments, like elements will be denoted bylike numbers from FIGS. 6A and 6B with an added leading numeral toindicate the same general feature in the additional embodiment. Thedescription of the above elements is applicable to the elementsdescribed below unless otherwise indicated.

Referring now to FIGS. 7A and 7B, another form of the present inventionis shown. In this embodiment, the inter-component gap 318 includes afirst ledge 326 and a second ledge 328 separated by a step 330. Ifnon-axial shear stress is applied between the first component 310 andthe second component 312, then the step 330 may provide a surfaceperpendicular to the applied force to reduce the shear stress loadapplied on the surfaces parallel to the applied force. It should beappreciated that a step could be also be formed between the firstcomponent 310 and the second component 312 such that when a torsionalforce is applied about the axis C-C, inducing tangential shear stressesin the brazed joint, at least a portion of the brazed joint is formed tobe outside of a surface of highest shear stress.

The flow control features at the inner periphery and the outer peripheryof the inter-component gap 318 also differ from the embodimentpreviously shown. The first component 310 has a lip 332 along the innerperiphery (that being the periphery closest to the axis C-C). The lip332 allows for brazing material 324 to be directed into theinter-component gap 318. Along the outer periphery, the first component310 has a lip 334 and the second component 312 has a lip 336. Theseparation of the lips 334 and 336 again provides a local increase inthe spacing between the first component 310 and the second component 312that inhibits the flow of the brazing material 324 past the outerperiphery of the inter-component gap 318. Thus, the brazing material 324is substantially retained between the components 310 and 312 to form thebrazed joint. This is shown in FIG. 7C, which displays the brazed partafter the brazing material 324 has flowed between the brazed surfaces314 and 316 and solidified to braze the components 310, 312 together.

Referring now to FIG. 8, a component configuration between brazedsurfaces 414, 416 is shown that is similar to the componentconfiguration in FIGS. 7A and 7B, but with slightly modified flowcontrol features formed on the outer periphery of the inter-componentgap 418. In particular, the second component 412 has a dam 438 formed onthe outer periphery that inhibits the flow of the brazing material 424from the inter-component gap 418 past the dam 438. The dam 438 is aportion of the second component 412 that is vertically raised to preventthe flow of the brazing material 424 away from the location of thebrazed joint. In the form shown, the top of the dam 438 is as high asany other part of the inter-component gap 418, such that no brazingmaterial 424 will be lost over the top of the dam 438 unless theinter-component gap 418 is entirely full of brazing material 224.

The dam 438 may or may not be coupled with other flow control features.For example, in the embodiment shown in FIG. 8, the dam 438 is used inconjunction with the lip 434 on the first component 410. The lip 434inhibits the flow of brazing material 424 about the outer periphery ofthe inter-component gap 418, while the dam 438 provides additionalprotection against the loss of brazing material 424. However, it iscontemplated that the dam could be also used without a lip nearby.

Referring now to FIG. 9, yet another form of the present invention isshown in which the step 530 is at a slightly inclined angle instead ofperpendicular to the first ledge 526 and the second ledge 528 as in theconfiguration shown in FIG. 8. When inter-component gaps like theseintersect at an angle, whether it be a right angle or some other angle,when a torsional force is transmitted through the joint, shear stressesare induced over all of the gaps in which the braze joint material joinsthe components. Thus, it may be desirable to configure the gaps in thisway to distribute the stresses.

Referring now to FIGS. 10A and 10B, an embodiment is shown in which thestep 630 is longer. Further, there is a lip 640 along theinter-component gap 618 at the intersection between the first ledge 626and the step 630, which creates a widening at the intersection of thesesurfaces. The lengthening of the step 630 may be desirable as theincreased length increases the distribution area over which a shearstress is applied when the first component 610 is axially twistedrelative to the second component 612.

Additionally, the lip 640 between the first ledge 626 and the step 630serves the function of preventing all the material located on the firstledge 626 from flowing over the dam 638. As the first ledge 626 iselevated well above the dam 638, there will be a tendency for any brazematerial to want to flow from the first ledge 626, down the step 630,across the second ledge 628 and up and over the dam 638 due to gravity.Although the lip 634 proximate the dam 638 tends to form a meniscus thatprovides sufficient surface tension to prevent the brazing material fromflowing past the lip 634, if there is enough elevated brazing material,then the meniscus may not be sufficiently strong to retain the brazingmaterial in all portions of the inter-component gap 618. Thus, the lip640 between the first ledge 626 and the step 630 may be used to helpisolate the brazing material on the first ledge 626 from the brazingmaterial in the step 630 and the second ledge 628 to retain all of thebrazing material in the inter-component gap 618.

Thus, the flow control features described herein help to retain thebrazing material within the inter-component gap during the brazingprocess. This reduces the likelihood of overflow occurring, creating acondition in which there is not enough brazing material to fill the gap.This further allows for the production of brazed joints having somewhatmore complex geometries without the loss of braze material. By alteringthe geometry of the brazed joint, the total area over which certaintypes of stresses are applied is increased. This results in an overallstrengthening of the brazed joint.

Many modifications and variations to these preferred embodiments will beapparent to those skilled in the art, which will be within the spiritand scope of the invention. Therefore, the invention should not belimited to the described embodiments. To ascertain the full scope of theinvention, the following claims should be referenced.

What is claimed is:
 1. A brazed part including a first component and asecond component brazed together by a brazing material, the brazed partcomprising: a plurality of locating joints, each of the plurality oflocating joints including: a projection on one of the first componentand the second component; and a corresponding recess on the other of thefirst component and the second component; wherein, in each of theplurality of locating joints, the projection is located in thecorresponding recess to define an inter-component gap between the firstcomponent and the second component, in which inter-component gap isreceived a brazing material that brazes the first component and thesecond component together, the inter-component gap being sized so as tofacilitate transport of a liquid phase of the brazing materialtherethrough via capillary action; and at least one lip disposed on atleast one of the first component and the second component at a peripheryof the inter-component gap, the lip providing a gradual increase of theinter-component gap at the periphery; a flow control feature formedbetween a first section and a second section of the inter-component gap,the first section and the second section not being in the same plane,the flow control feature being an internal lip that reduces a capillaryforce of the brazing material proximate the internal lip to inhibit theflow of the brazing material from the first section to the secondsection of the inter-component gap during brazing; wherein, duringbrazing, the gradual increase of the inter-component gap at theperiphery produces a meniscus in the liquid phase of the brazingmaterial having a surface tension sufficient to retain the brazingmaterial in the inter-component gap for solidification.
 2. The brazedpart of claim 1, wherein, in each of the plurality of locating joints,the projection has an arcuate convex surface and the correspondingrecess has opposite-facing angled walls and wherein, in each of theplurality of locating joints, the projection is located in thecorresponding recess and is supported by contact between the arcuateconvex surface and at least one of the angled walls.
 3. The brazed partof claim 2, wherein the arcuate convex surface is semi-spherical andeach of the angled walls contacted by the arcuate convex surface isessentially planar.
 4. The brazed part of claim 1, wherein the firstcomponent and the second component are joined together via brazing attheir respective brazing surfaces and wherein, during brazing, thebrazing material is heated to form a liquid that flows through theinter-component gap to wet the brazing surfaces and join the brazingsurfaces upon solidification.
 5. The brazed part of claim 1, wherein theat least one lip inhibits the capillary action of the brazing materialpast the periphery of the inter-component gap during brazing.
 6. Thebrazed part of claim 1, further comprising a dam that is verticallyraised from the brazing surface of at least one of the first componentand the second component and wherein the dam inhibits the flow of thebrazing material past the dam to further substantially retain thebrazing material within the inter-component gap.
 7. The brazed part ofclaim 1, wherein, when the brazed part is subjected to a rotationalstress about an axis resulting in an applied shear stress between thefirst and second components, at least one of the first section andsecond section extend along an essentially axial direction to increasean area over which the shear stress is applied.
 8. The brazed part ofclaim 1, wherein the brazed part is a planetary gear carrier such thatthe first component is a cage having at least three legs and the secondcomponent is a plate and wherein a locating joint is located betweeneach of the at least three legs and the plate to define at least threeinter-component gaps between the cage and the plate.
 9. The brazed partof claim 1, wherein the at least one lip on at least one of the firstcomponent and the second component at the periphery of theinter-component gap includes a lip on the first component at theperiphery of the inter-component gap and a lip on the second componentat the periphery of the inter-component gap.
 10. The brazed part ofclaim 9, wherein the lip on the first component and the lip on thesecond component separate from one another to provide a local increasein spacing between the first component and the second component thatinhibits the flow of the brazing material past the outer periphery ofthe inter-component gap.
 11. A method of forming a brazed part, themethod comprising: locating a first component relative to a secondcomponent by mating a plurality of locating joint portions of the firstcomponent with a plurality of locating joint portions of the secondcomponent to form a plurality of locating joints, each of the pluralityof locating joints including a projection on one of the first componentand the second component and a corresponding recess on the other of thefirst component and the second component, the first component beingpositioned relative to the second component such that a brazing surfaceof the first component and a brazing surface of the second componentdefine an inter-component gap therebetween; introducing a brazingmaterial into the inter-component gap; heating the brazing material toat least a melting point of the brazing material to form a liquid thatflows through the inter-component gap toward a periphery of theinter-component gap by wetting the brazing surfaces of the firstcomponent and the second component; substantially retaining the brazingmaterial within the inter-component gap by use of at least one lipdisposed on at least one of the first component and the second componentat a periphery of the inter-component gap, the at least one lipproviding a gradual increase of the inter-component gap at the peripherythat, upon receiving a flow of the liquid of the brazing material,produces a meniscus in the liquid of the brazing material having asurface tension that retains the brazing material in the inter-componentgap for solidification; and solidifying the brazing material to form abrazed joint between the first component and the second component;wherein a flow control feature is formed between a first section and asecond section of the inter-component gap, the first section and thesecond section not being in the same plane, the flow control featurebeing an internal lip that reduces a capillary force of the brazingmaterial proximate the internal lip to inhibit the flow of the brazingmaterial from the first section to the second section of theinter-component gap during brazing.
 12. The method of claim 11, whereinthe first component and the second component each have at least threelocating joint portions, each of the at least three locating jointportions being one of a projection with an arcuate convex surface and arecess with opposite-facing angled walls; and wherein the step oflocating the first component relative to the second component includesmating the at least three locating joint portions of the first componentand the at least three locating joint portions of the second componentto form at least three locating joints that define the inter-componentgap, each of the at least three locating joints including a projectionand a recess, such that the arcuate convex surface of the projectioncontacts at least one of the opposite-facing angled walls of the recess.13. The method of claim 11, wherein the step of introducing the brazingmaterial comprises placing the brazing material in a blind hole andwherein, during the step of heating the brazing material, the brazingmaterial moves to and wets by capillary action at least a portion of theinter-component gap between the first component and the secondcomponent.
 14. The method of claim 11, wherein the step of introducingthe brazing material comprises placing the brazing material in therecess of the locating joint and wherein, during the step of heating thebrazing material, the brazing material moves to and wets by capillaryaction at least a portion of the inter-component gap between the firstcomponent and the second component.
 15. The method of claim 11, whereinthe step of introducing the brazing material to at least one of thefirst component and the second component occurs before locating thefirst component relative to the second component, such that during theheating step, as the brazing material melts, a distance between thefirst component and the second component decreases and locates the firstcomponent relative to the second component by self-seating the locatingjoint portions of the first component into the locating joint portionsof the second component to form the locating joints.